//
//  main.c
//  LianXi
//
//  Created by 张木林 on 3/8/24.
//

#include <stdio.h>
struct ListNode* mergeTwoLists(struct ListNode* list1, struct ListNode* list2) {
    if(list1 == NULL)
    
        return list2;
    
    if(list2 == NULL)
    
        return list1;
    
    struct ListNode *tail = NULL,*head = NULL;
    while(list1 && list2)
    {
        if(list1->val<list2->val)
        {
            if(tail == NULL)
            {
                head = tail =list1;
            }
            else
            {
                tail->next = list1;
                tail = tail->next;
            }
            list1 = list1->next;
        }
        else
        {
            if(tail == NULL)
            {
                head = tail =list2;
            }
            else
            {
                tail->next = list2;
                tail = tail->next;
            }
            list2 = list2->next;
        }
    }
    if(list1)
    
    tail->next = list1;
    
    if(list2)
    
        tail->next = list2;
        return head;
    


}

//合并两个有序链表
